Table 1.
Perinatal Characteristics of the Study Sample (N=791)
| Variables | All (N=791) | Early Term (n=110) | Full Term (n=533) | Late Term (n=148) |
|---|---|---|---|---|
| Sex, % female | 52.0 | 54.5 | 51.4 | 52.0 |
| Gestational age, wks | 39.7 (1.0) | 37.7 (0.4) | 39.7 (0.4) | 41.1 (0.3) |
| Socioeconomic position, % manual | 27.3 | 31.8 | 26.3 | 27.7 |
| Birth weight, kg | 3.433 (0.478) | 3.233 (0.492) | 3.445 (0.473) | 3.532 (0.465) |
| Birth weight, Z scores | 0.02 (1.03) | 0.52 (1.12) | 0.03 (0.99) | −0.38 (0.89) |
| Mode of delivery, % | ||||
| Vaginal (normal) | 81.3 | 71.8 | 82.2 | 85.1 |
| Vaginal (assisted instrumental)a | 14.2 | 20.0 | 13.1 | 13.5 |
| Cesarean | 4.5 | 8.2 | 4.7 | 1.4 |
| Breastfeeding, % | ||||
| Never | 82.4 | 81.8 | 82.2 | 84.8 |
| ≤3 Mo | 11.1 | 12.7 | 10.7 | 11.5 |
| >3 Mo | 6.5 | 5.5 | 7.1 | 4.7 |
| Maternal age, y | 27.8 (5.6) | 27.6 (5.9) | 28.0 (5.6) | 27.1 (5.0) |
| Maternal BMI, kg/m2 | 24.6 (4.0) | 24.7 (4.3) | 24.5 (3.8) | 24.8 (4.1) |
| Normal weight, % | 65.0 | 62.7 | 65.9 | 65.5 |
| Overweight, % | 26.5 | 29.1 | 25.5 | 28.4 |
| Obese, % | 8.5 | 8.2 | 8.6 | 8.1 |
| Maternal smoking habits, % | ||||
| Non‐smoker | 63.5 | 67.3 | 63.8 | 59.5 |
| Sporadic smoker | 3.8 | 3.6 | 3.2 | 6.1 |
| Regular smoker | 32.7 | 29.1 | 33.0 | 34.5 |
Data are mean (SD) unless otherwise indicated. BMI indicates body mass index.
a
Including forceps or vacuum (ventouse).